27. Yang Liwei was picked from the 14 candidates for the Chinese space adventure and became China’s first astronaut _______ his great efforts.

our brother serve in the army—No, not now. But he ________ in the armyfor 8 years.

What the teacher said in class set all the _____ a lot.[ ]

In the old days, cows ________ farm work.

It is Jim, together with his cousins, that ________ for this terrible accident.